Chemical lesions skin layers

Common observations show that the chemical lesion does not appear within the very first second of contact with a corrosive. They occur progressively but quickly, from the surface of the skin toward the deeper layers. After the contact, a diffusion process through the different skin layers starts. Then, the chemical reacts with biochemical components, leading to cellular and tissular injury (Fig. 3.2). Four main parameters condition the seriousness of a chemical skin lesion ... 

The epithelium, the most superficial cellular layer of the cornea of the eye, is chemically less resistant than the keratinized epidermis of the skin. However, during ocular accidents, we know that it takes a few seconds for the first lesions to appear. This delay is bound to multiple factors, winking reflex, protective and diluting effect of the lachrymal liquid, effect of sweeping of the palpebral movements. After a short period, a kinetic of diffusion will set up in a variable way according to the nature of the corrosive. 

Cutaneous exposure may be selected to simulate the main route of human exposure and as a model for induction of skin lesions. During skin absorption, the chemical applied is transferred from the outer surface of the skin through the homy layer, the epidermis, the comeum, and into the systemic circulation. Absorption of chemicals through the skin is time-dependent, and this can be demonstrated by the application of occlusive bandages to prevent loss of the test material from the application site. Solid chemicals and chemicals soluble in secretions of the skin may dissolve in the secretions to a variable extent. 

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